Back in July, looking back on his first term, President Obama cited as his biggest mistake his failure “to tell a story to the American people.” We know that Obama has told plenty of stories, and Joe Biden pitched in Thursday at the Democratic National Convention to repeat one of the doozies — that “Barack had to sit at the end of his mom’s hospital bed and watch her fight cancer and fight her insurance companies at the same time.”

Obama may have called the Republican convention a “rerun,” but many can’t believe that Biden is repeating this episode, a story which made the campaign rounds in 2008 and was retold in the campaign film “The Road We’ve Traveled,” despite being debunked several times.

Research done by journalist Janny Scott for her biography, “A Singular Woman: The Untold Story of Barack Obama’s Mother,” disputes the idea that Stanley Ann Dunham had to fight the insurance companies. A White House spokesman didn’t challenge the book’s version of events, responding only, “The president has told this story based on his recollection of events that took place more than 15 years ago.”

Biden teared up earlier in the evening when accepting the nomination for vice president, but forgive us if we don’t reach for the tissues on this one.